This invention relates generally to a warhead exploder influence system, and more particularly to a torpedo exploder firing system for use against surface and submarine targets.
A variety of electromagnetic warhead influence firing systems have been developed for use in torpedos. These systems are divided into two major classes, the "RXE" and "RXEO" systems. The "RXE" design is characterized by orthogonal, internally mounted source and sensor coils, and envelope detection is used to amplify sensor signals. Sensor null balance is achieved by adjusting the sensor coil position and by manually adjusting an "in-phase" and a "quadrature" control within the warhead system. The sensitivity pattern produced by orthogonal source and sensor coils is highly directive, being sensitive above and below the torpedo and insensitive forward and abeam of the torpedo. This directivity pattern is effective against surface ships but results in an intolerable variation in firing range on collision course trajectories when used against a submarine target.
The RXEO design is subdivided into two classes, the "RXEO vertical look" and "RXEO 360.degree. look" systems. The "RXEO vertical look" system incorporates surface mounted transmitter coils in the torpedo afterbody, while the sensor coils are placed in a plastic nose section. The large distance between the source and sensor coils minimizes the direct induced voltages. However, to achieve sensor null in this system, it is necessary to manually adjust the position of the sensor coils and to operate "in-phase" and "quadrature" controls. This system only has vertical look capabilities, and is therefore unsuitable for use against submarine targets. The "RXEO 360.degree. look" system exhibits a sensitivity pattern that is constant about the torpedo roll or longitudinal axis with a maximum sensitivity along that axis. The 360.degree. look pattern is achieved by placing the sensitive axis of the nose mounted sensor coil in line with the transmitter coil axis in a co-linear geometry. The source coils are surfaced mounted in the torpedo afterbody, while the receiving coil is mounted in the plastic nose section. Nulling is obtained by driving an opposite-polarity field from a small coil placed near the sensor coil which carries a portion of the transmitter coil current. In addition, an adjustable position metal plate, brass or steel, is located near the sensor coil to provide a "quadrature" null adjustment. This system suffers, however, from unresolved sea water unbalance problems, and delay in the generation of influence signatures as the torpedo passes under the rail of the target. Since the transmitter coils and receiver coils of the RXEO system are in two different sections of the torpedo, the system suffers from noise and alignment problems. In addition, these sections are not readily interchangeable, since it is necessary to re-align the coil configuration.
Since the receiver coils of the prior art system are mounted internally in the torpedo sections, it is necessary to make the shells out of material that does not greatly attenuate the returning signal generated by the target. Consequently, non-attenuating materials such as plastic, fiberglass, or titanium must be used in the receiver section which greatly add to the cost of the torpedo.
Neither of the prior art systems is capable of operating against both submarine and surface targets. Furthermore, the excessive noises in both systems produced by alignment problems prevent firing at the optimal stand-off range. Consequently, the explosive charge is not used to its optimum capability.